Method of constructing a spark wheel

ABSTRACT

A method of constructing a spark wheel for cigarette lighters and the like which comprises subjecting the peripheral surface of a cylindrical blank to a knurling action to form a series of angular grooves separated by upwardly extending peaks, then cutting the peaks off to form relatively flat land portions between the grooves, and then cutting the land portions by a series of cuts extending parallel to the axis of the blank and angularly intersecting the knurled grooves, to form a series of linearly arranged teeth around the periphery of the blank.

United States Patent 1191 Biese'nbach 1111 3,742,753 1451 v July 3,1973

[ 1 METHOD OF CONSTRUCTING A SPARK WHEEL [76] Inventor: Ginn Biesenbach,120 Madison Avenue, Reading, Pa.

[22] Filed: Aug. 16, 1972 1 [21] Appl. No.: 280,954

[52] US. Cl 72/340, 29/558, 76/101 R,

76/101 A [51] Int. Cl B21d 28/00 [58] Field of Search 431/273, 274, 269,

[56] References Cited UNITED STATES PATENTS 2,455,348 12/1948 Barstow76/101 A 2,070,730 2/1937 Hellstrom 76/24 2,297,983 10/1942 Rea l48/12.4

11/1937 Freas 29/78 2,497,400 2/1950 Elier 29/105 3,528,665 9/1970Reduchm. 274/46 3,654,692 4/1972 Goetz 29/558 Primary Examiner-CharlesW. Lanham Assistant Examiner-James R. Duzan Attorney-Arthur A. Jacobs [57] ABSTRACT A method of constructing a spark wheel for cigarettelighters and the like which comprises subjecting the peripheral surfaceof a cylindrical blank to a knurling action to form a series of angulargrooves separated by upwardly extending peaks, then cutting the peaksoff to form relatively flat land portions between the grooves, and thencutting the land portions by a series of cuts extending parallel to theaxis of the blank and angularly intersecting the knurled grooves, toform a series of linearly arranged teeth around the periphery of theblank,

5 Claims, 6 Drawing Figures METHOD OF CONSTRUCTING A SPARK WHEEL Thisinvention relates to spark wheels adapted to be rotated against a flintto form a spark for igniting either a fuel-fed wick or a jet ofinflammable gas, such as used in cigarette lighters and the like, and itparticularly relates to a method of producingsuch spark wheels.

Spark wheels are generally cylindrical objects which have an abrasiveperipheral surface. The abrasive surface generally comprises a series ofhard teeth or ridges which are arranged in a series of .rows across theperipheral surface and which also extend up from the surface in aninclined direction, the inclination of all the teeth being in the samegeneral direction toward the peripheral surface.

The general practice, heretofore, was to manufacture these teeth by coldchiseling, which is primarily a tedious and difficult operation thatinvolves much man- Other objects and many of the attendant advantages ofthis invention will be readily appreciated as the same becomes betterunderstood by reference to the following description when read inconjunction with the accompanying drawings wherein:

FIG. I is a perspective view of a cigarette lighter equipped with aspark wheel embodying the present invention.

FIG. 2 is a side elevational view showing the basic first stepsembodying the method of the present invention.

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2.

FIG. 4 is a fragmentary, sectional view showing the spark wheel in itsintermediate form, after it has been processed in the manner shown inFIGS. 2 and 3.

FIG. 5 is a front elevational showing the second step in the methodembodying the present invention.

FIG. 6 is an elevational view, showing the completed periphery of thewheel.

Referring now in greater detail to the various figures of the drawingswherein similar reference characters refer to similar parts, there isshown in FIG. 1 a cigarette lighter, generally designated 10, which is,for the most part, of standard construction, and comprises a two-parthousing 12 including an outer casing 14 and a hollow insert 16 whichisadapted to hold cotton wadding or the like and a wick. The cottonwadding is adapted to be saturated with lighter fluid and enwraps thewick which receives the fluid from the wadding. The end of the wick,indicatedat 18, extends through an aperture in the top of the insert 16and is shielded on three sides by a wind-screen 20. The fourth side isopen to sparks emitted from a spark wheel 22 which is rotatable mountedon pin 24 between a pair of spaced ears 26.

The spark wheel 22 had a peripheral, abrasive, sparking surface made ofhard metal, such as case hardened, nitrided steel alloy, and, as hasbeen indicated above, this abrasive surface was heretofore, generallyformed by cold chiseling methods, whereby abrading teeth were formed inthe surface. i

In accordance with the method of the present invention, the coldchiseling processing is considerably reduced by machine methods. Asillustrated in FIGS. 2 and 3, the spark wheel blank, indicated at 28,formed from a solid base, is rotated on spindle 30 between a knurlingtool 32 and an oppositely-disposed stationary blade 34. The blade 34 isheld in position by a bracket 36 mounted on a rod 38 held by asupporting bracket 40. The blade 34 is releasably held in position in avertical slot 42 in the bracket 36 by set screws 44 in such manner thatthe blade may be removed, replaced, or adjusted toward and away from theblank 28.

In operation of the knurling tool 32, as it rotates in conjunction withthe rotation of the blank 28, a series of angular grooves 46 are formedin the peripheral surface of the blank. As shown in FIG. 4, the grooves46 are formed by pressing into the metal of the blank in a swagingaction rather than by cutting. The pressure forming the groovesdisplaces the metal upward between the grooves to from peaks 48 ateither side of each groove 46. This is shown in FIG. 4.

As indicated above, the peripheral surface of the spark wheel must beabrasive. Such abrasive surface is formed by upstanding teeth. Theseteeth must not only I extend transversely of the peripheral surface, ingeneral parallelism with the wheel axis, but must also extend in aninclined direction upwardly from the surface, so that when the wheel isrotated relative to the flint, the teeth will not abrade the fingers butwill effectively strike against the flint. The knurling action itselfdoes not provide such teeth because it merely provides a series ofdiagonal grooves which, because the grooves are uninterrupted, retainsthe relatively smooth contour on the periphery of the wheel. It is,therefore, necessary to provide further steps to form the teeth.

The further steps to form the teeth include, first, the use of theblade'34. As the blank 28 rotates between the knurling tool 32 and theblade 34, the knurling is provided first and then the blade 34 shavesoff the peaks 48, formed by the displaced metal of the knurling action.As the blank continues to rotate, the blade 34 continues to shave offthe displaced metal formed by the continuous knurling action until, whenthe blank is completed, flat, plateau-like land portions 50 are providedbetween each of the knurled grooves (see FIG. 4). v

In the next step, shown in FIG. 5, the knurled blank is subjected to theaction of a blade or chisel 52. In this operation, the blank is rotatedin timed relationship with a reciprocating blade 52. The blade 52 cutsinto the land portions 50 in a direction which is generally parallel tothe axis of the blank and, therefore, at"an angle relative to theknurled grooves 46 (as best seen in FIG. 6). The working edge 54 of theblade 52 is inclined on its upper surface and is straight on its lowersurface, whereby the land portions 50 are cut in a plane which isinclined relative'to the peripheral surface of the blank, so that aseries of linearly arranged, inclined teeth are formed. 7

All of the above steps take place while the metal of the blank is stillin a relatively soft or unhardened c'ondition. When these steps havebeen completed, the blank is then nitrided or case hardened in thestandard manner to form the finished wheel.

The invention claimed is:

1. A method of making a spark wheel which comprises knurling theperipheral surface of a cylindrical blank to form alternate, angularlydirected grooves and peaks in said peripheral surface, removing theupper portions of said peaks to form flat-topped land portions, cuttingsaid land portions by a series of cuts each of which extends across saidperipheral surface in a direction parallel to the axis of said blank andangular to said grooves, each of said cuts forming a line of teeth witheach tooth having an upper edge defined by a relatively straight frontwall and an inclined rear wall.

2. The method of claim 1 wherein said blank is rotated between aknurling tool adjacent a first peripheral portion of the blank and ashaving tool adjacent a second peripheral portion of the blank, saidblank being knurled at said first peripheral portion simultaneously withthe removal of said peaks by said shaving tool at the second peripheralportion.

3. The method of claim 2 wherein said shaving tool is stationary butadjustable relative to said blank.

4. The method of claim 1 wherein said cuts are formed by a reciprocablecutting tool which moves in timed relationship with the rotation of saidblank while said blank is being rotated relative to said cutting tool.

5. The method of claim 4 wherein said cutting tool has a cutting portiondefined by an angular upper edge

1. A method of making a spark wheel which comprises knurling the peripheral surface of a cylindrical blank to form alternate, angularly directed grooves and peaks in said peripheral surface, removing the upper portions of said peaks to form flat-topped land portions, cutting said land portions by a series of cuts each of which extends across said peripheral surface in a direction parallel to the axis of said blank and angular to said grooves, each of said cuts forming a line of teeth with each tooth having an upper edge defined by a relatively straight front wall and an inclined rear wall.
 2. The method of claim 1 wherein said blank is rotated between a knurling tool adjacent a first peripheral portion of the blank and a shaving tool adjacent a second peripheral portion of the blank, said blank being knurled at said first peripheral portion simultaneously with the removal of said peaks by said shaving tool at the second peripheral portion.
 3. The method of claim 2 wherein said shaving tool is stationary but adjustable relative to said blank.
 4. The method of claim 1 wherein said cuts are formed by a reciprocable cutting tool which moves in timed relationship with the rotation of said blank while said blank is being rotated relative to said cutting tool.
 5. The method of claim 4 wherein said cutting tool has a cutting portion defined by an angular upper edge and a straight lower edge. 